Coasts

• What is hydraulic action in coastal erosion?

  Waves generate pressure in cliff weaknesses
• How does hydraulic action weaken cliffs and headlands?

  It dislodges rock by squeezing air into joints
• Where is hydraulic action most pronounced on cliffs?

  Near the base of cliffs and headlands
• What is corrasion also known as?

  Abrasion
• How does corrasion erode cliffs and headlands?

  Loose material in waves hits the rock
• What happens to material as cliffs erode due to corrasion?

  More material becomes loose and falls into the sea
• What causes the acidity in natural water?

  Carbon in the atmosphere forms carbonic acid
• What type of weathering is solution?

  Chemical weathering
• How does solution affect limestone cliffs?

  It dissolves minerals, weakening the rock structure
• What is salt weathering?

  Mechanical weathering caused by salt crystals
• How do salt crystals contribute to weathering?

  They grow in rock weaknesses, enlarging them
• What is honeycomb weathering?

  A pattern of holes in rock from salt weathering

  
• How do plant roots contribute to mechanical weathering?

  They expand in gaps, breaking up the rock
• What role do burrowing animals play in weathering?

  They break up rock along weaknesses
• What are the most important processes for N5 in coastal erosion?

  Hydraulic action, corrosion, and solution

  
• What is attrition in coastal processes?

  It smooths materials in the sea
• How does attrition affect materials in the sea?

  It breaks them up into smaller pieces
• What type of coastlines do headlands and bays form on?

  Discordant coastlines

  
• How do headlands and bays form?

  Soft rock erodes faster than hard rock

  
• What is wave refraction?

  Waves bend around headlands, concentrating energy
• What forms when two caves erode through a headland?

  A coastal arch
• What happens to the keystone of a coastal arch over time?

  It weakens and eventually collapses
• What is a coastal stack?

  An isolated pillar of rock from an arch
• What is a wave-cut notch?

  A section of rock with no support underneath
• What is a wave-cut platform?

  A flat area extending into the sea
• How do wave-cut platforms form?

  Through erosion at the base of cliffs
• How are caves marked on OS maps?

  With the word "Cave" or "Caves"
• What does the wind rose indicate?

  The direction and strength of winds

  
• What causes waves to form?

  Surface friction exerted by winds
• How do waves change shape as they approach the shore?

  They become elliptical due to friction
• What is longshore drift?

  A zig-zag movement of material along the beach
• What is the swash in wave movement?

  The forward movement of the wave
• How does longshore drift contribute to beach formation?

  It moves material along the beach
• What are spits?

  Arms of land extending across a bay
• How do spits form?

  Through deposition of sand by waves
• What are bayhead bars?

  Sand bars connecting land across a bay
• What conditions are necessary for bayhead bars to form?

  Low energy water flow from estuaries
• What is a lagoon?

  A body of water behind a sand bar
• How do salt marshes form?

  Through sediment accumulation in lagoons
• What is a tombolo?

  A spit connecting an island to the mainland